"ACR does not do a good job with Canon RAW files. This is primarily because they don't use optimal coefficient for individual color channels during demosaic. This causes the unusually high color noise in the output. The grain is also too large and intrusive in subsequent processing.

The FPN comes from the sensor itself however its amplitude is exaggerated by ACR kernel. Here is an examples.... "

i do have some issues with the grain from LR myself (canon 5D MK2, 50D, 550D).

not color noise so much (i mostly shoot at iso 100-400) but i often think the grain is to big. DPP looks different and often more pleasing to my eye.... unfortunately DPP lacks in workflow.